Field of the Invention
The invention relates to a semiconductor component and a manufacturing method thereof and more particularly relates to a power MOSFET and a manufacturing method thereof.
Description of Related Art
In current semiconductor devices, power metal oxide semiconductor field effect transistors (MOSFETs) are used in a large quantity of electronic equipments, including power sources, automobile electronics, computers, and battery-powered devices, such as smartphones. Power MOSFETs can be used for a wide variety of applications, for example, connecting a power source to a switch of a specific electronic device having a load.
A power MOSFET applies an appropriate voltage to a gate of a power MOSFET, such that the device begins to conduct, so as to form a channel connecting a source and a drain of the power MOSFET, allowing current to flow. When the power MOSFET begins to conduct, the relationship between the current and the voltage substantially presents as a linear relationship, such that the device can serve the purpose of resistance.
Generally, transistors (including power MOSFETs) in a conducting state should have lower drain-source resistance. Vertical power MOSFETs achieve a low drain-source resistance effect by disposing the drain on a surface opposite another surface of the source contact. Disposing the drain on the opposite surface relative to the source contact shortens the conducting path of the current, thereby reducing the drain-source resistance.
However, when packaging transistors using wafer level chip scale packaging (WLCSP), all contacts (including source contact, drain contact, and gate contact) are required to be disposed on the same surface (on the same side) of the package. Only such configuration can easily connect the surface connected to each transistor terminal in the package to the circuit board using solder balls. Therefore, disposing the drain and the drain contact on the surface opposite the surface of the source contact raises difficulty in packaging the power MOSFET since such configuration must simultaneously provide electrical connection to the two opposite sides of the package. Therefore, the industry is still currently in dire need of a packaging method capable of enabling the power MOSFET to maintain good electrical efficiency and low drain-source resistance.